1. School of Computer Science and Engineering, Central South University , Changsha, Hunan 410083, China
2. School of Computer Science, University of South China , Hengyang, Hunan 421001, China
3. Department of Health Outcome and Biomedical Informatics, University of Florida , Gainesville, FL 32611, United States
4. Center for Artificial Intelligence in Drug Discovery, School of Medicine, Case Western Reserve University , Cleveland, OH 44106, United States